395 research outputs found

    Genetic basis of Campylobacter colonisation in the broiler chicken and its impact on intestinal health following natural field exposure

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    Campylobacter is the leading bacterial cause of foodborne diarrheal illness in humans and source attribution studies unequivocally identify handling or consumption of poultry meat as a key risk factor. Campylobacter colonizes the avian intestines in high numbers and rapidly spreads within flocks. A need therefore exists to devise strategies to reduce Campylobacter populations in poultry flocks. There has been a great deal of research aiming to understand the epidemiology and transmission characteristics of Campylobacter in poultry as a means to reduce carriage rates in poultry and reduce infection in humans. One potential strategy for control is the genetic selection of poultry for increased resistance to colonization by Campylobacter. The potential for genetic control of colonization has been demonstrated in inbred populations following experimental challenge with Campylobacter where quantitative trait loci associated with resistance have been identified. Currently in the literature there is no information of the genetic basis of Campylobacter colonization in commercial broiler lines and it is unknown whether these QTL are found in commercial broiler lines. The aim of this study was to estimate genetic parameters associated with Campylobacter load and genetic correlations with gut health and production traits following natural exposure of broiler chickens to Campylobacter. The results from the analysis show a low but significant heritability estimate (0.095 ± 0.037) for Campylobacter load which indicates a limited genetic basis and that non-genetic factors have a greater influence on the level of Campylobacter found in the broiler chicken. Furthermore, through examination of macroscopic intestinal health and absorptive capacity, our study indicated that Campylobacter has no detrimental effects on intestinal health and bird growth following natural exposure in the broiler line under study. These data indicate that whilst there is a genetic component to Campylobacter colonization worthy of further investigation, there is a large proportion of phenotypic variance under the influence of non-genetic effects. As such the control of Campylobacter will require understanding and manipulation of non-genetic host and environmental factors

    Time-Frequency based Feature Selection for Discrimination of non stationary Biosignals.

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    This research proposes a generic methodology for dimensionality reduction upon time-frequency representations applied to the classification of different types of biosignals. The methodology directly deals with the highly redundant and irrelevant data contained in these representations, combining a first stage of irrelevant data removal by variable selection, with a second stage of redundancy reduction using methods based on linear transformations. The study addresses two techniques that provided a similar performance: the first one is based on the selection of a set of the most relevant time?frequency points, whereas the second one selects the most relevant frequency bands. The first methodology needs a lower quantity of components, leading to a lower feature space; but the second improves the capture of the time-varying dynamics of the signal, and therefore provides a more stable performance. In order to evaluate the generalization capabilities of the methodology proposed it has been applied to two types of biosignals with different kinds of non-stationary behaviors: electroencephalographic and phonocardiographic biosignals. Even when these two databases contain samples with different degrees of complexity and a wide variety of characterizing patterns, the results demonstrate a good accuracy for the detection of pathologies, over 98%.The results open the possibility to extrapolate the methodology to the study of other biosignals

    Defining the timing of respiratory syncytial virus (RSV) outbreaks: an epidemiological study

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    BACKGROUND: Seasonal RSV infections occur every year and affect particularly children under six months of age. Passive immunoprophylaxis with monoclonal antibody Palivizumab is recommended in the period with high risk of RSV infection. This study aims to define the period for the southern part of Germany (Stuttgart area). METHODS: Epidemiological analysis of the RSV situation in southern Germany from 1996 to 2004 and comparison of results with literature was made. The respiratory tract specimens were sent in for the detection of RSV mainly by paediatric clinics. Detection of RSV was carried out mainly by real-time RT-PCR or by ELISA "Pathfinder". RSV outbreaks were depicted as an absolute number and as a percentage of RSV diagnoses in a month. Onsets, offsets, peaks, duration and severity of RSV seasons were defined and analysed. RESULTS: An early season with strong RSV activity (early-high phase) was followed by a weaker late season (late-low phase) in a regular biennial rhythm. However, onsets, offsets and durations of outbreaks varied significantly from year to year. RSV epidemics in southern Germany were found to oscillate in an antiphase with RSV epidemics in Finland and Sweden. CONCLUSION: The long-term regular biennial rhythm allows predicting whether the next outbreak will be late or early and whether RSV activity will be strong or weak. Not foreseeable, however, is the precise time of increase and decrease of RSV activity. Moreover, the regular seasonal pattern may be disrupted by irregular outbreaks. Thus, activity of RSV has to be monitored every year to define the period with high risk of infection

    The biology of inequalities in health: The LIFEPATH project

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    Socioeconomic differences in health have been consistently observed worldwide. Physical health deteriorates more rapidly with age among men and women with lower socioeconomic status (SES) than among those with higher SES. The biological processes underlying these differences are best understood by adopting a life course approach. In this paper we introduce the pan- European LIFEPATH project which uses multiple cohorts - including biomarker data - to investigate ageing as a phenomenon with two broad stages across life: build-up and decline. The ‘build-up’ stage, from conception and early intra-uterine life to late adolescence or early twenties, is characterised by rapid successions of developmentally and socially sensitive periods. The second stage, starting in early adulthood, is a period of ‘decline’ from maximum attained health to loss of function, overt disease and death. LIFEPATH adopts a study design that integrates social science and public health approaches with biology (including molecular epidemiology), using well-characterised population cohorts and omics measurements (particularly epigenomics). LIFEPATH includes information and biological samples from 17 cohorts, including several with extensive phenotyping and repeat biological samples, and a very large cohort (1 million individuals) without biological samples (WHIP, from Italy). The countries that are covered by the cohorts are France, Italy, Portugal, Ireland, UK, Finland, Switzerland and Australia. These cohorts are only a small proportion of all cohorts available in Europe, but we have chosen them for the combination of good measures of socioeconomic status, risk factors for non-communicable diseases (NCDs) and biomarkers already measured (or availability of blood samples for further testing). The majority of cohorts include ‘hard’ outcomes (diabetes, cancer, Cardiovascular Disease (CVD), total mortality), and the extensively phenotyped cohorts also include several measurements of the functional components of healthy ageing, including frailty, impaired vision, cognitive function, renal and brain function, osteoporosis, sleep disturbances and mental health. All age groups are represented with two birth cohorts, one cohort of adolescents and several cohorts encompassing young adults (age 18 and above). Furthermore, there is a strong representation of elderly subjects in seven cohorts. The specific objectives of the project are: (a) to show that healthy ageing is an achievable goal for society; (b) to improve the understanding of the mechanisms through which healthy ageing pathways diverge by SES, by investigating life course biological pathways using omic technologies; (c) to examine the consequences of the current economic recession on health and the biology of ageing (and the consequent increase in social inequalities); (d) to provide updated, relevant and innovative evidence for healthy ageing policies (particularly ‘health in all policies’) using both observational studies and an experimental approach based on a reanalysis of data from a ‘conditional cash transfer’ randomised experiment in New York and new data collected as part of an earned income tax credit randomised experiment in Atlanta and New York. To achieve these objectives, data are used from three categories of studies: 1. national census-based followup data to obtain mortality by socioeconomic status; 2. cohorts with intense phenotyping and repeat biological samples; 3. large cohorts with biological samples. With these objectives and methodologies, LIFEPATH seeks to provide updated, relevant and innovative evidence to underpin future policies and strategies for the promotion of healthy ageing, targeted disease prevention and clinical interventions that address the issue of social disparities in ageing and the social determinants of health. The present paper describes the design and some initial results of LIFEPATH as an example of the integration of social and biological sciences to provide evidence for public health policies
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